DNA coding for antigen protein of rinderpest virus

ABSTRACT

A DNA coding for an entire or a part of an antigen protein of the rinderpest virus; a protein for the production of the DNA comprising the steps of preparing an mRNA from the rinderpest virus, preparing a cDNA library from the mRNA, selecting a cDNA coding for the target protein from the cDNA library, and cloning the selected cDNA in a cloning vector; and a protein for the production of the antigen protein of the rinderpest virus comprising the steps of transfecting a vector containing the DNA coding for the target protein into animal cells, culturing the animal cells to produce the antigen protein, and recovering the target protein from the cell culture.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to DNA coding for antigen proteins of the rinderpest virus, a process for the production of that DNA, and a process for the production of the antigen protein using that DNA.

2. Description of the Related Art

Rinderpest is often prevalent in many areas of the world, such as the Middle and Near East, and Africa etc., and therefore, there is intensive research into the development of vaccines for the rinderpest virus.

In the development of vaccines through genetic engineering, processes wherein a gene coding for an antigen protein of the vaccine is expressed in E. coli, yeast or animal cells to obtain the antigen protein, and processes wherein a gene coding for an antigen protein is integrated into a vaccinea virus to construct a recombinant virus for the production of a live vaccine are known. To carry out such processes, a gene coding for an antigen protein of the rinderpest virus must be cloned.

A rinderpest virus strain L that can be grown in Vero cells has been constructed (F. Kobune et al., Archives of Viroloqy, 68, 271-277, 1981). Also, a rinderpest virus strain L (L 13) that can be grown in Vero cells has been developed (J. Gen. Virol. 67, 271, 1986).

The cloning of a cDNA coding for an F protein of the canine distemper virus has been disclosed by S. E. H. Russell, J. Gen. Virol. 66, 435-441, 1985.

Nevertheless, a gene coding for an antigen protein of the rinderpest virus has not yet been cloned.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a cloned genes coding for antigen proteins of the rinder-pest virus and a process for the production of that gene, and a process for the production of an antigen protein which is promising as an active ingredient for vaccines against the rinderpest virus.

More particularly, the present invention provides a DNA coding for an entire or a part of an antigen protein of the rinderpest virus.

The present invention also provides a process for the production of the above-mentioned DNA comprising the steps of:

preparing an mRNA from the rinderpest virus;

preparing a cDNA library from the mRNA;

selecting a cDNA coding for the target protein from the cDNA library; and

cloning the selected cDNA in a cloning vector.

The present invention also provides a process for the production of the above-mentioned protein comprising the steps of:

transfecting a vector containing the DNA coding for the target protein into animal cells;

culturing the animal cells to produce the antigen protein; and

recovering the target protein from the cell culture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents a restriction enzyme cleavage map of a cDNA insert RV-H in a plasmid pDH-RVH and a restriction enzyme cleavage map of a cDNA insert RV-F in a plasmid pDH-RVF;

FIG. 2 represents a restriction enzyme cleavage map of a cDNA insert RV-H-2 in a plasmid pDH-RVH-2 and a restriction enzyme cleavage map of a cDNA insert RV-F-2 in a plasmid pDH-RVF-2, wherein the thick line in the RV-H-2 represents a portion corresponding to a nucleotide sequence coding for a hemagglutinin protein (H protein) of the rinderpest virus shown in FIG. 3; and,

FIGS. 3-1 to 3-4 represent a nucleotide sequence containing a hemagglutinin gene of the rinderpest virus, wherein, in the sequence, ATG at the 2lst to 23rd position is a translation start codon and TAG at the 1848th to 1850th position is a translation stop codon, and a reading frame flanked by these codons (represented by a thick line in FIG. 2, RV-H-2) shows the codes for a hemagglutinin protein.

FIGS. 4-1 to 4-5 represent a nucleotide sequence containing a fusion protein gene of the rinderpest virus, wherein, in the sequence, ATG at the 587th to 589th position is a translation start codon and TAG at the 2225th to 2227th position is a translation stop codon, and a reading frame flanked by these codons (represented by a thick line in FIG. 2, RV-F-2) shows the codes for a fusion protein.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A. Cloning of genes

Since it is believed that the proteins effective as antigens to the rinderpest virus are the hemagglutinin protein (H protein) and the fusion protein (F protein), according to the present invention, the genes coding for these proteins were cloned.

(1) Extraction of mRNA

The rinderpest virus L strain that can be grown in Vero cells (rinderpest virus L 13 strain) was cultured, mRNA was extracted from the culture, and the cDNA was prepared from the mRNA according to the Okayama-Berg method (Okayama and Berg, Mol. Cell Boil., 2, 161-170, 1983; and Mol. Cell Biol., 3, 280-289, 1983).

More specifically, the rinderpest virus L 13 was used as an origin of the mRNA. The L 13 strain was obtained by fusing a rabbit lymphocyte infected with a rabbit-adapted passaged strain of the rinderpest virus (L-lapinized strain and F-Vero cells) under polyethylene glycol, and passaging 15 generations. Sub-confluent F-Vero cells in eight Petri dishes each having a diameter of 6 cm were inoculated with the L 13 strain at an m.o.i. of 1. The culture was passaged on teh next day, and 24 hours after the passage, 20 μg/ml of actinonycin D was added to the culture to inhibit a synthesis of cellular mRNA and incubation was continued for an additional 5 hours. The recovered cells were centrifuged in 6 M of guanidium isothiocyanate (GTC), 5 mM of sodium citrate and 0.5% of Sarkosyl - 5.7 M of CsCl and 0.1 M of EDTA at 35,000 rpm (150,000 XG) for more than 12 hours, according to the guanidinum-cesium chloride method, to recover the RNA (T. Maniatis et al., Molecular Cloning, p 196, 1982).

The thus-recovered RNA was then applied to an oligo (dT) cellulose column, and the adsorbed RNA was eluted by 10 mM Trsi-HCl (pH 7.5) buffer containing 1 mM EDTA and 0.05% SDS to obtain a poly A.sup.(+) RNA according to a known procedure (T. Maniatis et al., Molecular Cloning, p 197, 1982).

(2) Preparation of probes

According to the present invention, to confirm the presence of a target mRNA in the above-prepared poly A.sup.(+) RNA, and to screen cDNA library as described hereinafter in detail, an H gene of a subacute sclerosing panencephalitis (SSPE) virus was used as a probe (designated as H gene probe or SSPE-H-cDNA probe) to detect and screen the gene coding for the H protein (H gene) of the rinderpest virus; and the F gene of the canine distemper virus (CDV) was used as a probe (designated as F gene probe or CDV-F-cDNA probe) to detect and screen the gene coding for an F protein (F gene) of the rinderpest virus These genes were selected as probes because the above-mentioned SSPE virus and CDV, as well as the rinderpest virus, belong to the common genus Morbillivirus and these riruses are closely related to each other, and therefore, it is considered that the nucleotide sequences thereof will have a high homology.

The above-mentioned probes were prepared by obtaining an SSPE virus DNA and CDV DNA and labeling these DNA with a radioisotope ³⁵ S (T. Maniatis et al., Molecular Cloning, p 109, 1982).

More specifically, a cDNA library was made from SSPE infected cells, and SSPE H cDNA was selected by the use of measles virus H probe (Billeter et al. 1984, Virology 145 195). (DV H DNA was made according to Russel et al. (1985) (J. Gen. Virol, 66 433.). Each DNA thus-prepared was incubated with three unlabeled deoxyribonucleotides dATP, dGTP and dTTP, and a ³⁵ S-labeled deoxyribonucleotide ³⁵ S-dCTP-γS in the presence of E. coli DNA polymerase I in a Tris-HCl (pH 7.8) buffer. The labeled DNA was then separated from unreacted ³⁵ S-dCTP-YS by a Sephadex G25 column.

(3) Detection of H protein mRNA and F protein mRNA in poly A.sup.(+) RNA

The poly RNA prepared as described above was denatured with glyoxal or formamide, and separated by Agarose gel electrophoresis, and the separated mRNAs were subjected to hybridization with the above-mentioned SSPE-H-cDNA probe or CDV-F-cDNA probe according to the conventional Northern hybridization method. As a result, a 1.96 kb mRNA which hybridizes with the SSPE-H-cDNA probe and a 2.2 kb mRNA which hybridizes with the COV-F-cDNA were detected. This result suggests that the poly A.sup.(+) RNA preparation includes an mRNA coding for the H protein of the rinder-pest virus and an mRNA coding for the F protein of the rinderpest virus.

(4) Preparation of cDNA library

A cDNA library was prepared from the

above-mentioned poly A.sup.(+) RNA preparation according to the Okayama-Berg method (Okayama H. and P. Berg, Mol. Cell Biol., 2, 161, 1982; and Mol. Cell Biol., 3, 280, 1983). As a vector, an oligo dT-tailed (T=17) plasmid primer (pcDV-1) and an oligo dG-tailed (G=12) pL-1 Hind III linker were used.

More specificially, 8 μg of the above-mentioned poly A.sup.(+) RNA, 2 μg of the dT-tailed plasmid primer (pcDV-1), 2 mM of four dNTPs including ³⁵ S-dCTP, and 20.6 units of a reverse transcriptase (RTase) were incubated in 40 μl of a reaction mixture containing 100 mM of Tris-Hcl (pH 8.3), 10 mM of MgCl₂, 140 mM of KCl, 2 mM of methylmercury hydroxide, 20 mM of mercaptoethanol, and 1 mM of RNase inhibitor at 42° C. for 60 minutes, to form a cDNA-plasmid To the reaction mixture, 3.5 mM of dCTP and 30 units of terminal transferase were added, resulting in the formation of 73.5 μ1 total volume of the reaction mixture The reaction mixture was subjected to reaction at 37° C. for 3 minutes, and 2.5 mM of EDTA containing 0.5% (final concentration) of SDS was added to the reaction mixture to terminate the reaction The reaction mixture was extracted with chloroform and phenol, and the DNA was then precipitated with ethanol.

The thus-prepared cDNA-plasmid was digested with 20 units of Hind III in 40 μ1 of a buffer containing 10 mM of Tris-HCl (pH 7.5), 50 mM of NaCl, 10 mM of MgCl and 1 mM of dithiothreitol, at 37° C for 2 hours. Then, 120 mg of the digested cDNA-plasmid and 35 μg of the PL-1 linker were incubated in 40 μ1 of a reaction mixture containing 0.1 M NaCl, 10 mM Tris-HCl (pH 7.8) and 1 mM EDTA, first at 65° C. for 5 minutes and that of 42° C. for 60 minutes, and the reaction mixture was then cooled to a room temperature to allow annealing. After the reaction mixture was cooled to 0° C., 0.3 μg of E. coli DNA ligase was then added to the reaction mixture, and the reaction mixture was incubated at 12° C. overnight.

Then, 200 mg of E. coli DNA ligase, 0.450 units of RNase H and 0.8 units of DNA polymerase were added to the reaction mixture to make the total volume of the mixture of 48 μ1, and the temperature of the reaction mixture was then increased stepwise to 12° C., 15° C., 20° C., and to 25° C., for 30 minutes at each temperature, resulting in digestion of an mRNA region, formation of a double-stranded cDNA and ligation of the resulting cDNA, to complete the construction of plasmids containing the cDNA.

The thus-obtained plasmids were used to transform Escherichia coli DH-5 and E. coli MCl061, and a cDNA library comprising 7,700 clones and a cDNA library comprising 7,300 clones (total 15,000 clones) were obtained from E. coli DN-5 and E. coli MCl061, respectively.

(5) Screening of cDNA library

From among the above-mentioned 15,000 clones, 109 clones were screened by the colony hybridization method. As a result, a clone hybridizing with the SSPE-H-cDNA probe and a clone hybridizing with CDV-F-cDNA were obtained These clones were designated as Escherichia coli DH-RVH and Escherichia coli DH-RVF respectively; and plasmids in these E. coli cells were designated as pDH-RVH and pDH-RVF. The size of cDNA insert (designated as RV-H) in the plasmid pDH-RVH was about 2.2 kb, and the size of the cDNA insert (designated as RV-F) in the plasmid pDH-RVF was about 1.6 kb. It was considered that these cDNA inserts contained approximately the entire coding regions for the H protein and F protein of the rinderpest virus, respectively

The above-mentioned Escherichia coli DH-RVH was deposited with the Fermentation Research Institute Agency of Industrial Science and Technology (FRI), Higashi 1-1-3, Yatabe-cho, Tsukuba-gun, Ibaraki-ken, Japan, as FERM BP-1165 under the Budapest treaty on Aug. 29, 1986. The above-mentioned Escherichia coli DH-RVF was deposited with the FRI as FERM BP-1164 under the Budapest treaty on Aug. 29, 1986.

By repeating the same procedure as described above, a clone hybridizing with teh SSPE-H-cDNA probe and a clone hybridizing with the SSPE-H-cDNA were obtained. These clones were designated as Escherichia coli DH-RVH-2 and Escherichia coli DH-RVF-2, respectively; and plasmids in these E. coli cells were designated as pDH-RVH-2 and pDH-RVF-2, respectively. The size of the cDNA insert (designated as RV-H-2) in the plasmid pDH-RVH-2 was about 3.2 kb, and the size of the cDNA insert (designated as RV-F-2) in the plasmid pDH-RVF-2 was about 2.4 kb. The RV-H-2 contained an entire coding region for the H protein of the rinderpest virus, and the RV-F-2 is considered to contain an entire coding region for the F protein of the rinderpest virus.

The above-mentioned Escherichia coli DH-RVH-2 was deposited with the FRI as FERM BP-1319 under the Budapest treaty on Mar. 24, 1987. The above-mentioned Escherichia coli DH-RVF-2 was deposited with the FRI as FERM BP-1318 under the Budapest treaty on Mar. 24, 1987.

(6) Restriction enzyme cleavage map

The restriction enzyme cleavage sites of the above-mentioned cDNA inserts were analyzed to determine restriction enzyme cleavage maps, according to a conventional procedure. FIG. 1 represents the restriction enzyme cleavage maps for the cDNA inserts RV-H and RV-F, and FIG. 2 represents the restriction enzyme cleavage maps for the cDNA inserts RV-H-2 and RV-F-2.

(7) Determination of nucleotide sequences of cDNAs coding for H protein and F protein

The plasmids pDH-RVH and pDH-RVH-2 were digested with restriction enzymes Bam HI, Pvu II, Pst I, Eco RI, Hind III, and Sma I, and DNA fragments of several hundred base pairs in length were separated. Each DNA fragment was inserted to a polylinker site of a phage M13 DNA, and the nucleotide sequence was determined according to the Sanger dideoxy chain termination method. The result is shown in FIGS. 3-1 to 3-4.

According to a similar procedure, nucleotide sequence coding for F protein was determined. The result is shown in FIGS. 4-1 to 4-5.

(8) Expression of gene

COS7 cells were cultured in a cell culture chamber in 1 ml of Eagle's minimum essential medium containing 10% felal calf serum at 37° C. for 24 hours. The DNA of the plasmid pDH-RVH-2was coprecipitated with calcium phosphate, and 1 μg of the precipitated DNA was transfected to the cultured COS7 cells. The cells were then treated with a DMEM medium containing 10% dimethyl sulfoxide and 5% fetal calfserum. Fresh medium was added to the cells, and culturing was carried out at 37° C. for two tothree days. The cells were then fixed withacetone, and were observed by an indirect fluorescent antibody technique using an antibody specific to the rubeola virus. In this technique, an antigen H reactive with the antibody was observed on the cells. In same manner, it was confirmed that the pDH-RVF and pDH-RVF2 expressed an antigen F.

The present cDNA coding for the hemagglutinin protein of the rinderpest virus, and the cDNA coding for the fusion protein of the rinderpest virus are useful as gene starting materials in a process for the construction of a recombinant virus by inserting them into, for example, a vaccinia virus, or in a process for the production of antigen proteins by expressing the cDNA in E. coli, yeast or animal cells.

Moreover, the present cDNA and fragments thereof are useful as hybridization probes for screening genes of different origin but containing a similar nucleotide sequence, such as cDNA of different origin. Moreover, the present cDNA and fragments thereof are useful as a component of a kit for the detection of the rinderpest virus and related viruses.

Note, the procedures disclosed in the present specification can be applied to the cloning of other cDNAs coding for an antigen protein or a part thereof of the rinderpest virus. Then cDNA are also covered by the present invention. 

We claim:
 1. A DNA coding for a hemagglutinin protein antigen of a rinderpest virus.
 2. DNA according to claim 1, wherein the DNA has the following nucleotide sequence:ATGTCCTCCC CAAGAGACAG GGTCAATGCC TTCTACAAAG ACAACCTCCA ATTTAAGAAC ACTCGAGTGG TTCTTAATAA AGAGCAGCTC CTGATAGAAA GGCCTTACAT GTTGCTGGCG GTGCTGTTTG TTATGTTCCT GAGCCTAGTG GGGCTGTTGG CCATTGCAGG TATCAGACTC CACCGAGCTG CTGTCAACAC AGCAGAGATC AACAGTGGTC TGACGACAAG CATTGATATT ACCAAGTCTA TTGAGTACCA GGTCAAGGAC GTCTTAACTC CCCTCTTCAA AATAATTGGA GATGAGGTCG GGCTGAGGAC ACCTCAGAGA TTCACAGATC TGACTAAATT CATATCAGAC AAGATTAAGT TCCTTAACCC TGATAAAGAG TACGACTTCA GGGATATTAA CTGGTGCATC AGTCCCCCAG AGAGAATCAA GATTAATTAT GATCAGTATT GTGCTCACAC AGCTGCTGAG GAGCTGATAA CTATGCTGGT CAATTCGTCT CTGGCAGGTA CTTCGGTACT ACCGACATCA TTAGTCAACT TGGGGAGGAG CTGTACCGGG TCCACAACGA CTAAAGGTCA ATTCTCTAAC ATGTCATTGG CTCTTTCAGG GATATACTCA GGTCGTGGCT ACAATATTTC ATCCATGATA ACAATCACTG AGAAAGGCAT GTACGGAAGC ACTTATCTAG TCGGGAAACA TAATCAGGGA GCCAGGAGGC CAAGCACTGC TTGGCAACGG GATTACCGAG TCTTTGAAGT AGGCATAATT AGAGAACTAG GACTGGGCAC ACCAGTGTTT CATATGACAA ACTACCTGGA GCTCCCAAGA CAGCCGGAAT TGGAGATCTG CATGCTAGCT CTAGGAGAGT TCAAATTAGC TGCCCTCTGC TTAGCTGATA ACTCTGTCGC ACTGCATTAC GGGGGGTTAA GGGACGACCA CAAGATCAGG TTTGTCAAAC TGGGAGTATG GCCATCACCA GCCGACTCAG ACACCCTGGC CACTCTTTCA GCAGTAGATC CGACCTTGGA TGGGCTCTAT ATCACAACTC ATAGGGGAAT CATAGCTGCA GGGAAGGCCG TATGGGTCGT CCCTGTGACG AGAACAGATG ACCAAAGGAA AATGGGACAG TGCCGCCGAG AGGCTTGTCG AGAGAAACCA CCACCTTTCT GTAACAGTAC AGATTGGGAG CCATTAGAGG CCGGCCGTAT ACCGGCATAT GGAATACTAA CTATCAGGCT GGGGCTGGCT GATAAGCTGA AATTGACCAT AATTTCAGAA TTTGGTCCCT TGATCACACA TGACTCAGGG ATGGACTTAT ACACCCCACT TGACGGTAAT GAGTACTGGC TGACTATTCC TCCATTGCAG AATTCAGCTT TAGGAACGGT GAACACCCTA GTTTTAGAGC CCAGTCTCAA AATTAGTCCT AACATCCTTA CTCTCCCCAT CAGGTCGGGG GGAGGTGACT GTTACACTCC CACTTACCTG TCAGACCTGG CCGATGATGA TGTTAAACTG AGCTCCAATC TTGTAATCCT CCCGAGTAGA AACCTCCAAT ATGTGTCAGC AACCTACGAC ACCTCTAGAG TTGAGCATGC CATTGTATAC TATATCTATA GCGCCGGGCG ACTATCATCG TATTACTACC CTGTTAAGTT GCCCATAAAG GGAGATCCTG TCAGCCTGCA GATAGGATGC TTCCCTTGGG GCCTCAAGCT ATGGTGCCAT CATTTCTGCT CTGTTATAGA TTCAGGAACT CGCAAGCAGG TCACCCATAC AGGGGCAGTA GGGATTGAGA TCACTTGCAA TAGCAGATAG
 3. A DNA coding for a fusion protein antigen of a rinderpest virus.
 4. DNA according to claim 3, wherein the DNA has the following nucleotide sequence:ATGG GGATCTTATT TGCTGCCCTG CTAGCAATGA CTAACCCACA CTTAGCTACT GGCCAGATCC ACTGGGGCAA CCTTTCAAAA ATTGGACTCG TAGGGACAGG TAGTGCCAGT TATAAGGTGA TGACCCAATC GAGTCACCAG TCACTAGTTA TAAAGCTGAT GCCCAATATC ACTGCTATAG ACAATTGCAC CAAAACAGAG ATTATGGAGT ACAAGAGGCT GTTGGGGACA GTGCTTAAGC CTATCAGGGA AGCTCTTAAC GCTATTACTA AGAACATAAA ACCAATCCAG AGTTCCACTA CCAGTAGGAG ACACAAGAGG TTCGCGGGAG TCGTTTTGGC TGGAGCCGCT CTCGGGGTTG CAACCGCAGC CCAGATTACA GCAGGGATTG CTCTTCATCA GACAATGATG AATTCCCAAG CTATCGAAAG TCTTAAGGCA AGTCTGGAAA CAACCAATCA AGCAATTGAG GAAATACGAC AAGCGGGTCA AGAAATGGTC CTAGCGGTTC AGGGTGTCCA AGATTACATC AACAATGAAC TGGTGCCTGC GATGGGCCAG CTATCGTGTG AAATTGTGGG TCAAAAGCTA GGGCTGAAAC TGCTTAGATA TTACACTGAA ATCTTGTCAT TATTTGGACC CAGCCTCAGG GACCCGGTCT CGGCTGAGCT TTCTATTCAG GCCTTAAGTT ACGCCTTGGG TGGGGACATT AATAAAATAC TAGAAAAGCT TGGGTATAGC CCCACTGATC TCCTTGCTAT ACTGGAAAGT AAGGGTATCA AGGCTAAGAT AACCTATGTG GATATCCAAA GTTACTTCAT TGTGCTCAGC ATAGCTTATC CGTCACTCTC CGAAATTAAG GGGGTGATAG TGCACCGTCT GGAGACTGTC TCTTACAATA TAGGATCGCA GGAGTGGTAC ACCACAGTAC CGCGGTATGT GGCAACCCAG GGTTACCTCA TTTCAAATTT CGATGACACA CCCTGTGCAT TCACTCCGGA GGGCACTATC TGCAGTCAAA ATGCAATATA CCCGATGAGC CCATTGCTCC AAGAATGTTT CCGTGGGTCA ACCAGGTCAT GTGCCCGTAC ACTGGTTTTG GGGTCCATAG GGAATAGGTT TATACTATCT AAGGGGAACC TCATTGGCAA CTGTGCCTCT ATTTTGTGCA AGTGCTACAC CACTGGCTCA ATAATAAGTC AAGACCCTGA CAAGATCCTA ACATATATAG CTGCAGACCA ATGCCCCGTC GTAGAAGTAG GCGGTGTAAC CATCCAGGTC GGGAGCAGGG AGTACTCCGA TGCAGTGTAC CTGCATGAAA TAGATCTTGG CCCACCAATA TCGCTAGAGA AGCTGGATGT GGGGACTAAC CTCTGGAATG CAGTGACAAA ATTGGAGAAA GCCAAGGATC TACTAGATTC ATCTGATCTG ATCCTGGAAA ACATCAAGGG TGTTTCAGTC ACGAACACAG GTTACATTOT AGTCGGAGTC GGGTTGATTG CAGTGGTGGG GATCCTCATT ATTACCTGTT GTTGTAAGAA GCGCAGGACT GACAACAAAG TCTCCACTAT GGTCTTGAAC CCGGGTCTTA GACCAGATCT TACTGGTACA TCTAAATCCT ACGTACGGTC GTTGTAG 